The primary goal of the Diagnosis and Symptom Assessment Core (DSAC) is to provide specialized diagnostic and psychiatric symptom assessment training and quality assurance procedures to projects and cores within the Translational Center for Neurocognition and Emotion in Schizophrenia. The DSAC will train interviewers who conduct screening and evaluation of patients across three phases of illness in the Prodromal Research Project, the Aftercare Research Program, and the Chronic Schizophrenia Recruitment and Assessment Core. The DSAC will be responsible for establishing and maintaining high levels of interrater reliability, preventing rater drift, and improving the reliability and validity of Center instruments. To accomplish these goals, the DSAC will: 1) maintain well standardized, comprehensive and reliable training and quality assurance methods for prodromal signs assessment, diagnosis of DSM-IV disorders, psychiatric symptom assessment, and measurement of insight, 2) maintain reliability standards and criteria for certification of diagnosticians, diagnostic interviewers, and symptom raters who use assessment instruments such as the SCID-I, SCID-II, SIPS, SOPS, BPRS, SANS, SAPS, and SUMD-R, 3) ensure high levels of interrater reliability for diagnosticians who will be conducting training and quality assurance procedures, and 4) expand the DSAC training videotape library to include updated structured interviews for generating diagnoses and symptom rating scales. Phase I of the training program requires that diagnostic interviewers and symptom assessors rate a minimum of six training videotapes and have interrater reliability calculated using the accompanying "Gold Standard" consensus diagnoses and ratings. For the SIPS, SOPS, BPRS, SANS, SAPS, and SUMD-R, we will require that the trainee obtain a minimum Intraclass Correlation Coefficient (ICC) of .80 across all items and all six training videotapes. These requirements must be met or the trainee will attend remediation sessions before "graduating" to Phase II of training, which requires conducting 4 "live" assessments for each measure. The DSAC will also formally evaluate interviewer style, e.g., ability to probe for symptoms. All interviewers will enter a quality assurance program aimed at preventing rater "drift." Each interviewer will be required to demonstrate, as evaluated with kappa and ICC statistics, high levels of interrater reliability by continuing to conduct "live" interviews and co-rating assessments conducted by a senior Center diagnostician. The DSAC will collaborate with other Cores for Clinical Samples and Center Projects around research questions such as instrument development, method development, and improving interrater reliability.